Sealing device

ABSTRACT

A sealing device for sealing off an opening between a shaft and a grease-lubricated split bearing housing comprises two halves divided by a diametrical cut and each having a main body arranged in a circumferential groove in the bearing housing opening. The sealing device is provided with sealing lips spaced apart from each other and forming an intermediate grease reservoir, and reinforcing portions arranged between the main seal body and the sealing lips to facilitate sealing engagement between the sealing lips and a shaft when an upper bearing housing half arranged with the upper seal half is mounted onto the shaft while the shaft is resting in a lower bearing housing half arranged with the lower seal half.

FIELD OF THE INVENTION

This invention generally relates to a sealing device. More particularly,the invention pertains to a sealing device for sealing off an openingbetween a shaft and a grease-lubricated split bearing housing, whereinthe sealing device generally includes a main body arranged in acircumferential groove in the bearing housing opening, with the sealingdevice being divided in two halves by a diametrical cut.

BACKGROUND OF THE INVENTION

For sealing off an opening between a shaft and a split bearing housing,sealing devices have been used which are in the form of sealing ringscomprising a main body and a sealing lip, with the sealing rings beingdivided in two halves by virtue of a diametrical cut.

When such a known sealing device is mounted in a bearing housing, oneseal half is positioned in a groove at an opening in the lower bearinghousing half and the shaft is positioned in the opening. Afterwards, theother seal half is positioned in a groove in the upper bearing housinghalf and the upper bearing housing half is positioned over the lowerhalf. Then, the two bearing housing halves are pressed against eachother.

Unfortunately, problems exist with this type of sealing device in thatthe sealing function can be relatively easily reduced to a significantextent or virtually lost. The sealing lip which engages the shaft whenthe two bearing housing halves are pressed against each other is weakand has a tendency of becoming partially folded during assembly. Thisfolding motion is quite difficult, if not virtually impossible, tovisually detect as the lip is normally hidden by the bearing housing.However, it will be apparent that the lip has been folded because thesealing function of the lip is significantly reduced or lost.

For other purposes, other known types of sealing devices have benemployed. These sealing devices function in ways other than thatdescribed above, for example by being provided with a plurality ofsealing lips to ensure good sealing.

U.S. Pat. No. 5,908,249 and U.S. Pat. No. 4,586,720 disclose sealingdevices in the form of sealing rings provided with a plurality ofsealing lips that are intended to be brought into sealing engagementagainst a bearing assembly. However, these sealing devices are used inspecific applications. For example, the sealing device disclosed in U.S.Pat. No. 4,586,720 relates to neck seals of the type employed on theroll necks of rolls in a rolling mill. The neck seal is intended toprevent water from infiltrating into the bearing and contaminating thebearing oil while at the same time preventing loss of oil from thebearing.

SUMMARY OF THE INVENTION

According to one aspect, a sealing device which seals off an openingbetween a shaft and a grease-lubricated split bearing housing comprisedof an upper bearing housing half and a lower bearing housing half,includes a main body arranged in a circumferential groove in the openingof the bearing housing and divided into two halves by a diametrical cut.The main body is provided with a pair of sealing lips spaced apart fromeach other, with an intermediate grease reservoir between the sealinglips. The main body also includes reinforcing portions arranged betweenthe main body and the sealing lips to facilitate sealing engagementbetween the sealing lips and the shaft when the upper bearing housinghalf provided with the upper seal half is mounted onto the shaft withthe shaft resting in the lower bearing housing half provided with thelower seal half.

According to another aspect, a sealing device sealing off an openingbetween a shaft and a lubricated bearing housing comprised of an firstbearing housing half and a second bearing housing half, includes a mainbody divided into first and second seal halves by a diametrical cut,with the first seal half being positioned in a circumferential groove inthe first bearing housing half and the second seal half being positionedin a circumferential groove in the second bearing housing half. Thefirst and second seal halves are each provided with a pair of sealinglips spaced apart from each other and reinforcing portions each arrangedbetween the main body and one of the sealing lips. The first and secondseal halves are each provided with an intermediate lubricant reservoirlocated between the sealing lips.

In accordance with another aspect, a bearing assembly includes alubricated bearing housing having a circumferential groove formed on aninner surface of the bearing housing and comprised of a first bearinghousing half and a second bearing housing half, a shaft, an openingbetween the shaft and the lubricated bearing housing, and a sealingdevice for sealing off the opening between the shaft and the lubricatedbearing housing. The sealing device includes a main body divided intotwo halves by a diametrical cut, and each arranged in thecircumferential groove of the bearing housing. The sealing device isalso provided with a pair of sealing lips spaced apart from each other,reinforcing portions arranged between the main body and the sealinglips, and an intermediate grease reservoir located between the sealinglips.

The sealing device is able to at least inhibit folding of the sealinglips during assembly of the split bearing housing, while also providingexcellent sealing effect and ease in assembly. Additionally, the sealingdevice at least inhibits the sealing lips from being worn down tooquickly because of pressure in the grease reservoir.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The foregoing and additional features and characteristics of the presentinvention will become more apparent from the following detaileddescription considered with reference to the accompanying drawingfigures in which like reference numerals designate like elements.

FIG. 1 is a top perspective view of the split sealing device accordingto an embodiment.

FIG. 2 is a cross-sectional view of the sealing device shown in FIG. 1.

FIG. 3 is an exploded view of various parts forming a bearing assemblyaccording to an embodiment, including the sealing device shown in FIG.1.

FIG. 4 is a cross-sectional view of the sealing device mounted in thebearing housing.

DETAILED DESCRIPTION OF THE INVENTION

Referring initially to FIG. 1, the sealing device 10 is substantiallyannular in shape and forms a ring-shaped or annular sealing elementwhich is split in two halves by a diametrical cut. The two halvesinclude an upper half or first seal half 12 and a lower half or secondseal half 14.

Considering the cross-section illustrated in FIG. 2, each half of thesealing device 10 is comprised of a one-piece main body 16. This mainbody 16 possesses a first end (i.e., the upper end in FIG. 2) providedwith a protrusion 18 and a shoulder 20 on either side of the protrusion.The protrusion 18 has a planar top surface 22 and outwardly inclinedside surfaces 24 which extend down to the shoulders 20. The protrusionthus increases in dimension towards the shoulders 20. The shoulders 20each have a planar surface 26 substantially parallel with the topsurface 22 of the protrusion 18.

The second end of the main body 16 (i.e., the lower end in FIG. 2) isprovided with sealing lips 28 and reinforcing portions 30. In thisillustrated embodiment, the second end of the main body 16 is providedwith two sealing lips 28 spaced apart from each other and forming anintermediate, generally axially extending, space 32 which serves as areservoir for grease lubricant. The reservoir 32 is substantiallyrectangular and preferably centered under the protrusion 18 of the mainbody 16. In addition, the reservoir 32 is preferably half as wide as theprotrusion 18, for example half as wide as the width of the protrusion18 at about the axial midpoint. The sealing lips 28 are directed ingenerally opposite directions away from the reservoir and are outwardlyconical or somewhat diagonally oriented.

Each of the two halves forming sealing device 10 also includes tworeinforcing portions 30 which are spaced from the shoulders 26. Thesereinforcing portions 30 are arranged outside the sealing lips 28, andbetween the main seal body 16 and the sealing lips 28. In addition, thereinforcing portions 30 are made with a material thickness of relativelysubstantial thickness and have a rather stiff design capable ofprotecting the sealing lips from large dirt particles and sustainingmost of the bending forces acting on the sealing device 10 duringassembly. The sealing lips 28, on the other hand, have a substantiallysmaller material thickness than the reinforcing portions 30 and aretherefore more easily bent.

Each half of the sealing device 10 is made in one piece by injectionmolding, using a material that is somewhat flexible, for example apolymeric material such as, for example, polyurethane.

FIGS. 3 and 4 illustrate how the sealing device 10 is mounted in abearing housing 34 to produce a bearing assembly. As mentioned above,the sealing device 10 is intended to be used to seal off an opening 36between a shaft 38 and a grease-lubricated split bearing housing 34. Thebearing housing 34 comprises two halves, an upper bearing housing half40 and a lower bearing housing half 42. The bearing housing opening 36is arranged with a circumferential groove 44 that is adapted to receivethe sealing device 10. More particularly, the circumferential groove 44is formed in the upper and lower bearing housing halves. The groove 44has a form or shape substantially corresponding to that of theprotrusion 18, but with the groove 44 having a rectangular cross-sectionas seen in FIG. 4. The width of the groove 44 is a bit smaller than thewidth of the protrusion 18 at the thickest portion of the protrusion 18.

Upon assembly, the lower seal half 14 is positioned in the groove 44 inthe lower bearing housing half 42. Because the protrusion 18 of thesealing device 10 is slightly larger than the width of the groove 44,the protrusion 18 has to be pressed into the groove 44 and is squeezed.The sealing device 10 is pressed so far into the groove 44 that theshoulders 20 are brought into contact with the bearing housing surface46 near to or adjoining the groove 44. Similarly, the upper seal half 12is positioned in the groove in the upper bearing housing half 40.Preferably, the reservoir 32 is then filled with grease lubricant.

A shaft 38 is positioned in the opening 36 in the lower bearing housinghalf 42, and the upper bearing housing half 40 is mounted onto the shaft38 and the lower bearing housing half 42. When pressing the two bearinghousing halves 40, 42 together, the sealing lips 28 are brought intosealing engagement with the shaft 38. An excellent and reliable sealingthus results by virtue of the stiff, bending resistant, reinforcingportions 30, the existence of which in the sealing device 10 at leastinhibits and preferably prevents the sealing lips 28 from folding.

During use of the bearing arrangement, the bearing housing 34 needs tobe filled up with new grease lubricant from time to time. However, whennew grease is pressed into the bearing housing 34, it is warmed up uponcontacting the warmer bearing and so a relatively large pressure isbuilt up inside the housing. Such pressure usually affects the sealinglips 28 in a negative manner in that they are pressed harder against theshaft 38, causing them to be quickly worn out. However, the reinforcingportions 30 provided in the sealing device here decrease this negativeeffect by carrying a large amount of the pressure so that the sealinglips are less exposed to such pressure.

The principles, preferred embodiment and mode of operation of thepresent invention have been described in the foregoing specification.However, the invention which is intended to be protected is not to beconstrued as limited to the particular embodiment disclosed. Further,the embodiment described herein is to be regarded as illustrative ratherthan restrictive. Variations and changes may be made by others, andequivalents employed, without departing from the spirit of the presentinvention. Accordingly, it is expressly intended that all suchvariations, changes and equivalents which fall within the spirit andscope of the present invention as defined in the claims, be embracedthereby.

1. A sealing device sealing off an opening between a shaft and agrease-lubricated split bearing housing comprised of an upper bearinghousing half and a lower bearing housing half, the sealing devicecomprising: a sealing element arranged in a circumferential groove inthe opening of the bearing housing, the sealing element being dividedinto two seal halves by a diametrical cut, with each seal halfcomprising a main body and each seal half being a one-piece seal half;the main body of each seal half being provided with a pair of sealinglips spaced apart from each other, with an intermediate grease reservoirbetween the sealing lips; the main body of each seal half alsocomprising reinforcing portions arranged between the main body and thesealing lips to facilitate sealing engagement between the sealing lipsand the shaft, with the reinforcing portions spaced from an outersurface of the shaft, when the upper bearing housing half provided withthe upper seal half is mounted onto the shaft with the shaft resting inthe lower bearing housing half provided with the lower seal half, thereinforcing portions projecting axially outside the sealing lips; andthe main body of each seal half possessing shoulders on which bear asurface of the bearing housing adjacent the groove, the reinforcingportions being arranged at a distance from the shoulders so as to bespaced apart from the shoulders, the sealing device contacting the shaftonly at the pair of sealing lips.
 2. The sealing device according toclaim 1, wherein the main body of each seal half also possesses aprotrusion positioned between and extending away from the shoulders, theprotrusion having a shape substantially corresponding to the groove ofthe bearing housing.
 3. The bearing assembly according to claim 2,wherein the sealing lips have a smaller material thickness than thereinforcing portions.
 4. The sealing device according to claim 1,wherein the reinforcing portions possess a material thickness greaterthan a material thickness of the sealing lips.
 5. The sealing deviceaccording to claim 1, wherein the sealing device is made of a polymericmaterial.
 6. The sealing device according to claim 1, wherein thesealing device is made of polyurethane.
 7. The sealing device accordingto claim 1, wherein the sealing device is comprised of two one-piecehalves.
 8. A sealing device sealing off an opening between a shaftpossessing an outer surface and a lubricated bearing housing comprisedof a first bearing housing half and a second bearing housing half, thesealing device comprising: an annular seal element divided into firstand second one-piece seal halves by a diametrical cut, each of the firstand second one-piece seal halves having a main body possessing one endat which is provided a protrusion positioned in a circumferential groovein one of the bearing housing halves, and an opposite end at which isprovided a pair of sealing lips spaced apart from each other andengaging the shaft; the first and second seal halves each havingreinforcing portions arranged between the main body and the sealinglips; each of the first and second halves possessing a pair of shoulderson which rests a surface of the bearing housing adjacent the groove, thereinforcing portions extending axially outside the shoulders; and thefirst and second seal halves each being provided with an intermediatelubricant reservoir located between the sealing lips, the reinforcingportions projecting axially outside the sealing lips, and thereinforcing portions being spaced from the outer surface of the shaft,the sealing device contacting the shaft only at the pair of sealinglips.
 9. The sealing device according to claim 8, wherein each of thefirst and second seal halves possesses a protrusion and the pair ofshoulders extending outwardly beyond an outer surface of the protrusion,a surface of the bearing housing resting on the shoulders.
 10. Thesealing device according to claim 9, wherein the protrusions possess awidth adjacent a tip end of the protrusion that is less than the widthof the protrusion adjacent the shoulders.
 11. The bearing assemblyaccording to claim 10, wherein the sealing lips have a smaller materialthickness than the reinforcing portions.
 12. The sealing deviceaccording to claim 8, wherein the reinforcing portions possess amaterial thickness greater than a material thickness of the sealinglips.
 13. The sealing device according to claim 8, wherein the sealingdevice is made of a polymeric material.
 14. The sealing device accordingto claim 8, wherein the sealing device is made of polyurethane.
 15. Abearing assembly comprising: a lubricated bearing housing having acircumferential groove formed on an inner surface of the bearing housingand comprised of a first bearing housing half and a second bearinghousing half; a shaft; an opening between the shaft and the lubricatedbearing housing; a sealing device sealing off the opening between theshaft and the lubricated bearing housing, the sealing device comprisingan annular seal element divided into two seal halves by a diametricalcut, and each seal half having a tapering protrusion positioned in thecircumferential groove of the bearing housing; each seal half being aone-piece seal half; each seal half comprising a main body provided witha pair of sealing lips spaced apart from each other and contacting theshaft, and reinforcing portions arranged between the main body and thesealing lips, the reinforcing portions projecting axially outside thesealing lips; each seal half also possessing shoulders on which bear asurface of one of the first bearing housing half and the second bearinghousing half adjacent the groove, the reinforcing portions beingarranged at a distance from the shoulders so as to be spaced apart fromthe shoulders; and each sealing half also being provided with anintermediate grease reservoir located between the sealing lips, thesealing device contacting the shaft only at the pair of sealing lips.16. The bearing assembly according to claim 15, wherein the protrusionon each seal half extends away from the shoulders.
 17. The bearingassembly according to claim 16, wherein the sealing lips have a smallermaterial thickness than the reinforcing portions.
 18. The bearingassembly according to claim 15, wherein the reinforcing portions possessa material thickness greater than a material thickness of the sealinglips.
 19. The bearing assembly according to claim 15, wherein thesealing device is made of a polymeric material.
 20. The bearing assemblyaccording to claim 15, wherein the sealing device is made ofpolyurethane.
 21. The bearing assembly according to claim 15, whereinthe sealing device is comprised of two one-piece halves.